     :stroke (name color)
     :stroke-width "10px"
     :fill "none"
-    ; :marker-start "url(#Vertex)"
     :marker-mid "url(#Triangle)"
-    ; :marker-end "url(#Vertex)"
     }])
 
 (def color->value {:red 1

    :markerHeight "3"
    :orient "auto"}
   [:svg:path {:d "M0,0 L 10,5 L0,10 z"}]])


(def circle-marker
  [:svg:marker
   {:id "Vertex"
    :refX "2"
    :refY "2"
    :markerWidth "5"
    :markerHeight "5"
    :orient "auto"}
   [:svg:circle
    {:fill "black"
     :stroke "none"
     :cx 2 :cy 2
     :r 2}]])


(defn make-line-dirs [from to]

    ch))


(def triangle-marker
  [:svg:marker
   {:id "Triangle"
